1) Field of the Invention
The present invention relates to a read head incorporating an image reading function.
2) Related Art of the Invention
Read heads have been widely used for facsimile systems, copying machines and the like. A conventional read head, for example, as shown in FIG. 7, is composed of a fluorescent tube 12 for illuminating a script 11, a convergent rod lens array 13, and a light receiving substrate 14 on which a plurality of light receiving elements 14b are mounted and arranged linearly. Since this kind of read heads have to use, as a light source, a fluorescent tube having a diameter of about 6 mm at most, the miniaturization thereof has been difficult. Even if light emitting diodes are used as a light source, there has been offered a disadvantage in that the distance between the light source and a medium to be read becomes longer.
These years, there has been a demand for a read head having a reading sensitivity which is linear with respect to the density of an image in order to read an image graph or an image having a density gradation from a medium to be read. Accordingly, it has been required to provide a read head which can irradiate light having a sufficient intensity to the medium to be read.